Non-oriented electrical steel sheet and method for manufacturing the same

ABSTRACT

A non-directional electrical steel sheet according to an embodiment of the present disclosure includes, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %) Ti, 0.005 wt % or less of (not including 0 wt %) 0.001 to 0.1 wt % of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, with the remainder being Fe and unavoidable impurities, and satisfies Formulas 1 to 3 below. 
       1.7≤[Si]([Al]+[Mn])≤2.9   [Formula 1]
 
       50≤13.25+11.3*([Si]+[Al][Mn]/2)≤60   [Formula 2]
 
       0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3]
 
     (In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent the content (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).

TECHNICAL FIELD

The present disclosure relates to a non-directional electrical steelsheet and a method for manufacturing the same.

BACKGROUND ART

A non-directional electrical steel sheet is mainly used in a device toconvert electrical energy into mechanical energy, and requires excellentmagnetic properties in order to achieve high efficiency in this process.The magnetic properties include core loss and flux density. Accordingly,when the core loss is low, the energy loss in the energy conversionprocess can be reduced, and when the flux density is high, greater powercan be generated is with the same electric energy. Therefore, energyefficiency of the motor can be increased when the non-directionalelectrical steel sheet has a lower core loss and a higher flux density.Generally, elements that increase specific resistivity are added orsteel sheet is rolled to a thin thickness to reduce the core loss of anon-directional electrical steel sheet.

The typical method of increasing the magnetic properties ofnon-directional electrical steel sheet is to add Si as an alloy element.While the addition of Si increases the specific resistivity of thesteel, and thus provides an advantage of reduced high-frequency coreloss, this also results in inferior flux density and deterioratedmachinability. That is, addition of too much Si can hinder cold rolling.In particular, the electrical steel sheet for high frequencyapplications can have less core loss when it is made with thinnerthickness, but the deteriorated machinability due to the addition of Sican serve as a fatal problem for the rolling of a thin film. Otherspecific-resistivity-increasing elements such as Al and Mn may be addedto overcome the machinability degradation due to Si addition.

The addition of these elements may reduce the core loss, but there is adisadvantage that the flux density is deteriorated due to increasedtotal alloy amount, and that the increased hardness of the material anddeterioration of machinability also hinder cold rolling, In addition, Aland Mn can combine with impurities unavoidably present in the steelsheet to minutely precipitate nitrides, sulfides, etc., in which casecore loss can be further increased. For this reason, a method is used,which controls impurities at a very low level in the steelmaking step ofthe non-directional electrical steel sheet to suppress the generation offine precipitates that impede the movement of the magnetic wall, therebylowering the core loss. However, the method for improving the core lossby way of high cleanliness of steel has the drawback that it is noteffective in improving the flux density, and it serves as a factor thatrather lowers the steel workability and increases the cost.

In order to improve the magnetic properties of non-directionalelectrical steel sheet, various methods have been proposed, such asthinning the product thickness, adding special elements to improvemagnetic properties, or optimizing the grain size and texture. Somemethods have been proposed, examples of which include a method ofimproving the magnetic properties of non-directional electrical steelsheet by adding REM, a method of making large grain size after annealingthe hot rolled sheet and performing cold rolling and recrystallizationannealing, a method of improving the magnetic properties by retainingthe {001}//ND orientation from the columnar grains using the slab havinga thickness of 50 mm or less, and the like. However, there is a problemin that when these methods are applied to the actual production process,the cost increases sharply, or the production using the existingfacilities is impossible, or the productivity drops considerably.

DISCLOSURE Technical Problem

The present invention has been made in an effort to provide anon-directional electrical steel sheet with excellent magneticproperties as well as high productivity, by precisely controlling thecontents of Si, Al and Mn among the additive components of steel.

Another embodiment of the present disclosure is to provide a method formanufacturing a non-directional electrical steel sheet.

Technical Solution

A non-directional electrical steel sheet according to an embodiment ofthe present disclosure includes, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % orless of (not including 0 wt %) C, 0.005 wt % or less of (not including 0wt %) Ti, 0.005 wt % or less of (not including 0 wt %) Nb, 0.001 to 0.1wt % of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, withthe remainder being Fe and unavoidable impurities, and satisfiesFormulas 1 to 3 below.

1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1]

50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2]

0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3]

(In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent thecontent (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).

The non-directional electrical steel sheet may further include 0.001 wt% or less of (not including 0 wt %) B, 0.005 wt % or less of (notincluding 0 wt %) Mg, Zr and V and 0.025 wt % or less of (not including0 wt %) Cu.

The density calculated by Formula 4 below may be 7.57 to 7.67 g/cm ³.

7.865+(−0.0611*[Si]−0.102*[Al]+0.00589*[Mn])   [Formula 4]

(In Formula 4, [Si], [Al] and [Mn] represent the contents (in wt %) ofSi, Al and Mn, respectively.)

Tensile test elongation may be 24% or higher.

The thickness may be 0.10 to 0.35 mm.

A method for manufacturing a non-directional electrical steel sheetaccording to an embodiment of the present disclosure includes steps of:heating a slab including, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt %of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %)S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of(not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %)Ti, 0.005 wt % or less of (not including 0 wt %) Nb, 0.001 to 0.1 wt %of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, with theremainder being Fe and unavoidable impurities, and satisfying Formulas 1to 3 below and then hot rolling the slab to manufacture a hot rolledsheet; cold rolling the hot rolled sheet to manufacture a cold rolledsheet; and recrystallization annealing the cold rolled sheet.

1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1]

50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2]

(In Formulas 1 and 2, [Si], [Al], and [Mn] represent the contents (in wt%) of Si, Al and Mn, respectively.)

The step of manufacturing the hot rolled sheet may include heating theslab to 1100 to 1200° C.

The step of manufacturing the hot rolled sheet may include hot rollingat a finish temperature of 800 to 1000° C.

After the step of manufacturing the hot rolled sheet, the method mayfurther include a step of annealing at a temperature of 850 to 1150° C.

The slab may further include 0.001 wt % or less of (not including 0 wt%) B, 0.005 wt % or less of (not including 0 wt %) Mg, Zr and V and0.025 wt % or less of (not including 0 wt %) Cu.

The density of the manufactured steel sheet calculated by Formula 4 maybe 7.57 to 7.67 g/cm³.

7.865+(−0.0611*[Si]−0.102*[Al]+0.00589*[Mn])  [Formula 4]

(In Formula 4, [Si], [Al] and [Mn] represent the contents (in wt %) ofSi, Al and Mn, respectively.)

The manufactured steel sheet may have a tensile test elongation of 24%or more.

The step of manufacturing the cold rolled sheet may include cold rollingto a thickness of 0.10 to 0.35 mm.

Advantageous Effects

The non-directional electrical steel sheet according to an embodiment ofthe present disclosure has excellent magnetic properties as well assuperior productivity.

MODE FOR INVENTION

The terms “first”, “second” and “third” as used herein are intended todescribe various parts, components, regions, layers and/or sections, butnot construed as limiting. These terms are merely used to distinguishany parts, components, regions, layers and/or sections from anotherparts, components, regions, layers and/or sections. Accordingly, a firstpart, component, region, layer or section to be described below may bereferred to as a second part, component, region, layer or sectionwithout departing from the scope of the present disclosure.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to limit the present disclosure.The singular forms used herein include plural forms as long as thephrases do not expressly mean to the contrary. As used herein, themeaning of “comprising” specifies specific features, regions, integers,steps, operations, elements and/or components, and does not exclude thepresence or the addition of other features, regions, integers, steps,operations, elements and/or components.

When a portion is referred to as being “above” or “on” another portion,it may be directly on another portion or may be accompanied by yetanother portion disposed in between. In contrast, when a portion isreferred to as being “directly above” another portion, no other portionis interposed in between.

Unless otherwise defined, all terms including technical and scientificterms used herein have the same meaning as commonly understood by thosewith ordinary knowledge in the art to which this invention belongs.Terms defined in the generally available dictionaries have a meaningcorresponding to a related technology document and presently disclosedcontents and are not analyzed as an ideal or very official meaningunless stated otherwise.

In addition, unless otherwise stated, % means wt %, and 1 ppm is 0.0001wt %.

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail to help those with ordinary knowledge in the arteasily achieve the present disclosure. As those skilled in the art wouldrealize, the described embodiments may be modified in various differentways, all without departing from the spirit or scope of the presentinvention.

A non-directional electrical steel sheet according to an embodiment ofthe present disclosure includes, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % orless of (not including 0 wt %) C, 0.005 wt % or less of (not including 0wt %) Ti, 0.005 wt % or less of (not including 0 wt %) Nb, 0.001 to 0.1wt % of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, withthe remainder being Fe and unavoidable impurities.

First, the reason for limiting the components of non-directionalelectrical steel sheet is explained.

Si: 2.5 to 3.3 wt %

Silicon (Si) plays a role of increasing the specific resistivity of thematerial to decrease the core loss. Addition of Si in an insufficientamount can result in less than desired improvement of the high-frequencycore loss. On the contrary, addition of too much Si can cause increasedbrittleness of the is material, resulting in drastically deterioratedrolling productivity. Accordingly, Si may be added in the rangedescribed above.

Al: 0.05 to 1 wt %

Likewise Mn, aluminum (Al) plays a role of increasing the specificresistivity to lower the core loss. The specific resistivity increase byAl is lower than that of Si, but when added in the proper amount, Al canincrease the specific resistivity while maintaining the rollingproperties. Addition of Al in an insufficient amount considerablyreduces the effect of improving the high-frequency core loss, and alsocauses formation of fine nitride and sulfide, which results indeteriorated magnetic properties. On the contrary, addition of too muchAl can drastically deteriorate the magnetic properties or rollingproperties. Accordingly, Al may be added in the range described above.

Mn: 0.05 to 1 wt %

Likewise Al, Manganese (Mn) plays a role of increasing the specificresistivity to decrease the core loss. Addition of Mn in an insufficientamount considerably reduces the effect of improving the high-frequencycore loss, and also causes formation of fine nitride and sulfide, whichresults in deteriorated magnetic properties. On the contrary, additionof too much Mn can drastically deteriorate the magnetic properties orrolling properties. Accordingly, Mn may be added in the range describedabove.

S: 0.01 wt % or less

Sulfur (S) is an element unavoidably present in the steel to form fineprecipitates such as MnS, CuS, and the like to deteriorate the magneticproperties. It is thus desired to limit S to 0.01 wt % or less or morespecifically, to 0.005 wt % or less.

N: 0.005 wt % or less

Nitrogen (N) not only forms fine and long AIN precipitates in the basematerial, but also combines with other impurities to form fine nitridethat suppresses the grain growth and exacerbate the core loss. It isthus desirable to limit N to 0.005 wt % or less, or more specifically,to 0.003 wt % or less.

C: 0.005 wt % or less

Carbon (C) causes self-aging and combines with other impurity elementsto produce carbide, thus deteriorating the magnetic properties. It isthus desirable to limit C to 0.005 wt % or less, or more specifically,to 0.003 wt % or less.

Ti: 0.005 wt % or less, Nb: 0.005 wt % or less

Titanium (Ti) and Niobium (Nb) form carbides or nitrides to deterioratecore loss and promote development of {111} texture detrimental to themagnetic properties. It is thus desirable to limit Ti and Nb to 0.005 wt% or less, or more specifically, to 0.003 wt % or less.

P: 0.001 to 0.1 wt %, Sn: 0.001 to 0.1 wt % Sb: 0.001 to 0.1 wt %

Phosphorus (P), tin (Sn), and antimony (Sb) are segregated on thesurfaces and the grain boundaries of the steel sheet, playing a role ofinhibiting the surface oxidation and inhibiting recrystallization of the{111}//ND orientation in the annealing process, thus improving thetexture, If any of these elements is added in an insufficient amount,effect thereof is considerably deteriorated, and if the elements areadded more than necessary, an increase in the amount of grain boundarysegregation suppresses grain growth, thus deteriorating core loss andlowering the toughness of steel, and deteriorating productivity, whichis not desirable. In particular, when the sum of P, Sn, and Sb islimited to 0.025 to 0.15 wt %, the surface oxidation inhibition andtexture improvement effect are maximized and the magnetic properties areremarkably improved.

Other Impurities

In addition to the elements described above, unavoidable impurities,such as B, Mg, Zr, V, and Cu may be incorporated. Although theseelements are in trace amounts, they may still cause deterioration ofmagnetic properties through formation of dross in the steel, and so on,and accordingly, the elements are managed to satisfy the followingconditions: B: 0.001 wt % or less, Mg, Zr, V: 0.005 wt % or less, andCu: 0.025 wt % or less.

The non-directional electrical steel sheet according to an embodiment ofthe present disclosure satisfies Formulas 1 to 3 below.

1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1]

50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2]

0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3]

(In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent thecontent (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).

When Formulas 1 to 3 are satisfied, both excellent magnetic propertiesand excellent rolling properties are provided, but outside this range,the magnetic properties or the rolling properties may deterioraterapidly.

The non-directional electrical steel sheet according to an embodiment ofthe present disclosure may have a density of 7.57 to 7.67g/cmDeletedTexts, as calculated by Formula 4 below. When the density isless than 7.5767g/cmDeletedTexts, the flux density may be deterioratedor the rolling properties may be decreased rapidly. When the densityexceeds 7.67 g/cm^(DeletedTexts) , the core loss may be deteriorated andespecially the high-frequency core loss may be seriously deteriorated.Accordingly, the density may be regulated to the range described above.

The non-directional electrical steel sheet according to an embodiment ofthe present disclosure may have a tensile test elongation of 24% orhigher. When the elongation is less than 24%, the rolling property isdeteriorated and results in deteriorated productivity. Morespecifically, the elongation may be 28 to 34%.

The non-directional electrical steel sheet according to an embodiment ofthe present disclosure may have a thickness of 0.10 to 0.35 mm.

A method for manufacturing a non-directional electrical steel sheetaccording to an embodiment of the present disclosure includes steps of:heating a slab including, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt %of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %)S, 0.005 wt % or less of (not to including 0 wt %) N, 0.005 wt % or lessof (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt%) Ti, 0.005 wt % or less of (not including 0 wt %) Nb, 0.001 to 0.1 wt% of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, with theremainder being Fe and unavoidable impurities, and satisfying Formulas 1to 3 below and then hot rolling the slab to manufacture a hot rolledsheet; cold rolling the hot rolled sheet to manufacture a cold rolledsheet; and recrystallization annealing the cold rolled sheet.

1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1]

50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2]

0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3]

(In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent thecontent (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).

First, the slab is heated and then hot rolled to prepare a hot rolledsheet. The reason for limiting the addition ratio of each composition isthe same as the reason for limiting the composition of thenon-directional electrical steel sheet described above. Since thecomposition of the slab does not substantially change during hotrolling, hot rolled sheet annealing, cold rolling, and recrystallizationannealing, and the like, which will be described below, the compositionof the slab remains substantially the same as that of thenon-directional electrical steel sheet.

The slab is charged into a furnace and then heated to 1100 to 1200° C.

The heated slab is hot rolled to 2 to 2.3 mm to manufacture a hot rolledsheet. The finish temperature at the step of manufacturing the hotrolled sheet may be 800 to 1000° C.

The hot rolled sheet after hot rolling is subjected to hot rolled sheetannealing at a temperature of 850 to 1150° C. When the hot rolled sheetannealing temperature is lower than 850° C., the structure does not growor grows too minutely to increase the flux density, and when theannealing temperature is higher than 1150° C., the magnetic propertiesare rather deteriorated and the rolling workability may deteriorate dueto the deformation of the sheet shape. Accordingly, the temperaturerange is limited to 850 to 1150° C. More preferably, the annealingtemperature of the hot rolled sheet may be 950 to 1150° C. The hotrolled sheet annealing may be performed as necessary, to increase theorientation favorable to the magnetic propertie, or may be omitted. Theaverage grain diameter after the hot rolled sheet annealing maypreferably be 120 μm or higher.

After the hot rolled sheet annealing, the hot rolled sheet is pickledand cold rolled to a predetermined thickness. While differentthicknesses may be applied depending on the thickness of the hot rolledsheet, the hot rolled sheet may be cold rolled to a final thickness of0.10 to 0.35 mm by applying a reduction ratio of about 70 to 95%.

The cold rolled sheet after final cold rolling is then subjected tofinal to recrystallization annealing. When the final recrystallizationannealing temperature is too low, sufficient recrystallization does notoccur, and when the final recrystallization annealing temperature is toohigh, rapid grain growth occurs and, resulting in deteriorated fluxdensity and high-frequency core loss. Accordingly, it is desirable toperform the final recrystallization annealing at a temperature of 850 to1150° C.

The recrystallization annealing sheet is treated with an insulatingcoating and shipped to the customer. The insulating coating may includean organic, inorganic or organic-inorganic composite coating, and othercoatings having insulating property may be used. The customer may usethe steel sheet as it is, or may use it after performing stressrelieving annealing, if necessary.

Hereinafter, the present disclosure is explained in more detail withreference to Examples. However, the Examples are described merely toillustrate the present disclosure, and the present disclosure is notlimited thereto.

EXAMPLE 1

The slab composed as shown in Table 1 was heated at 1100° C. and hotrolled at a finish temperature of 870° C. to prepare a hot rolled sheethaving a thickness of 2.3 mm. The hot rolled sheet was annealed at 1060°C. for 100 seconds, pickled, cold rolled to 0.35 mm thickness, and thensubjected to final recrystallization annealing at 1000° CC for 110seconds. Values of [Si]/([Al]+[Mn]), 13.25+11.3*([Si]+[Al]+[Mn]/2), and[P]+[Sn]+[Sb], density, flux density (B50), core loss (W15/50),high-frequency core loss (W10/400), and the bend test results andelongation with respect to the respective specimens are summarized inTable 2 below.

The density was expressed by the value calculated by the Formula7,865+(−0.0611*[Si]−0.102*[Al]+0.005891*[Mn]). For magnetic propertiessuch as flux density, core loss and high-frequency core loss, at leastthree specimen sheets in 60 mm*60 mm size were cut for each specimen,and then the magnetic properties in the vertical direction and therolling direction were measured with a single sheet tester. The averagesof the measurements obtained in the two directions are listed. In thiscase, ‘B50’ refers to the flux density induced in the magnetic field of5000 A/m, ‘W15/50’ is the core loss when 1.5 T flux density is inducedat the frequency of 50 Hz, and ‘W10/400’ refers to the core loss whenthe flux density of 1.0 T is induced at the frequency of 400 Hz. Thebend test was carried out to predict the rolling productivity. After thehot rolled sheet annealing, 2.3 mm-thick specimen was cut into 300 mm*35mm size, and subjected to the adhesion bend test at room temperature.The result was marked ‘poor’ when there occurred fracture such as crackat the outer bent surfaces and edges, or marked ‘good’ when there was nocrack. The elongation was expressed by the value obtained by tensiletest according to JIS-5 specification.

TABLE 1 Specimen Si Al Mn P Sn Sb C S N Ti Nb No. (%) (%) (%) (%) (%)(%) (%) (%) (%) (%) (%) A1 3.50 0.90 0.70 0.032 0.054 0.001 0.00270.0021 0.0023 0.0036 0.0032 A2 3.30 0.80 0.40 0.008 0.034 0.024 0.00300.0023 0.0019 0.0034 0.0014 A3 3.30 0.60 0.30 0.025 0.013 0.021 0.00210.0031 0.0034 0.0011 0.0023 A4 3.00 0.75 0.30 0.032 0.029 0.035 0.00280.0023 0.0032 0.0012 0.0026 A5 3.00 0.90 0.20 0.012 0.043 0.013 0.00250.0019 0.0017 0.0024 0.0019 A6 3.00 0.50 0.20 0.042 0.029 0.015 0.00240.0034 0.0017 0.0021 0.0023 A7 2.80 0.90 0.30 0.048 0.041 0.023 0.00320.0014 0.0029 0.0023 0.0019 A8 2.80 0.40 0.85 0.009 0.048 0.034 0.00310.0023 0.0014 0.0019 0.0031 A9 2.80 0.90 0.80 0.011 0.032 0.019 0.00290.0026 0.0032 0.0014 0.0017 A10 2.70 0.80 0.30 0.031 0.009 0.033 0.00290.0019 0.0017 0.0032 0.0031 A11 2.70 0.50 0.80 0.009 0.015 0.049 0.00210.0023 0.0029 0.0021 0.0032 A12 2.50 0.90 0.50 0.028 0.027 0.034 0.00270.0019 0.0014 0.0017 0.0017 A13 2.50 1.10 0.50 0.019 0.033 0.031 0.00330.0034 0.0014 0.0029 0.0021 A14 2.30 0.40 0.60 0.013 0.023 0.048 0.00230.0011 0.0023 0.0014 0.0017

TABLE 2 Specimen Formula 1 Formula 2 Formula 3 Density B50 W15/50W10/400 Bend No. Value Value Value [g/cm³] (T) (W/kg) (W/kg) testElongation Remarks A1 2.19 66.93 0.087 7.563 X X X Poor X Comp. Ex. A22.75 61.84 0.066 7.584 1.64 2.13 16.2 Poor 13.7 Comp. Ex. A3 3.67 59.020.059 7.604 1.65 2.16 16.8 Poor 14.4 Comp. Ex. A4 2.86 57.32 0.096 7.6071.68 2.03 15.7 Good 29.0 Ex. A5 2.73 58.45 0.068 7.591 1.68 2.01 15.7Good 29.4 Ex. A6 4.29 53.93 0.086 7.632 1.66 2.24 17.7 Good 32.1 Comp.Ex. A7 2.33 56.76 0.112 7.604 1.69 2.03 15.8 Good 30.9 Ex. A8 2.24 54.210.091 7.658 1.70 2.06 15.9 Good 31.6 Ex. A9 1.65 59.58 0.062 7.607 1.652.15 16.3 Poor 21.2 Comp. Ex. A10 2.45 54.50 0.073 7.620 1.69 2.06 16.0Good 31.6 Ex. A11 2.08 53.93 0.073 7.654 1.69 2.07 16.1 Good 31.5 Ex.A12 1.79 54.50 0.089 7.623 1.69 2.06 16.0 Good 32.4 Ex. A1 A13 1.5656.76 0.083 7.603 1.67 2.14 16.3 Good 33.2 Comp. Ex. A14 2.30 47.150.084 7.687 1.68 2.43 18.9 Good 34.8 Comp. Ex.

As shown in Table 1 and Table 2, Examples A4, A5, A7, A8, A10, A11, andA12 satisfying the conditions of the present disclosure exhibitedexcellent magnetic properties, and both good bend test results and goodelongation. On the other hand, Examples A3 and A6 having [Si]/[Al]+[Mn])above the range of the present disclosure exhibited inferior magneticproperties or poor bend test results and elongation, and Examples A9 andA13 having [Si]/([Al]+[Mn]) below the range of the present inventionalso exhibited inferior magnetic properties or poor bend test resultsand elongation. Examples A2 and A14 having 13.25+11.3*([Si]+[Al][Mn]/2)above or below the range of the present disclosure also exhibitedinferior magnetic properties or poor bend test results and elongation.

EXAMPLE 2

The slab composed according to Tables 3 and 4 were heated at 1130 □ andhot rolled at a finish temperature of 870 □ to prepare a 2.0 mm-thickhot rolled sheet. The hot rolled sheet was annealed at 1030 □ for 100seconds, pickled, and then cold rolled to 0.35 mm thickness, andsubjected to final recrystallization annealing at 990 □ for 110 seconds.Values of [Si]/([Al]+[Mn]), 13.25+11.3*([Si]+[Al][Mn]/2) , and[P]+[Sn]+[Sb], flux density (B50), core loss (W15/50), high-frequencycore loss (W10/400), and the bend test results and elongation withrespect to the respective specimens are summarized in Table 5 below.

TABLE 3 Specimen Si Al Mn P Sn Sb C S N No. (%) (%) (%) (%) (%) (%) (%)(%) (%) B1 2.90 0.80 0.30 0.032 0.029 0.043 0.0032 0.0012 0.0029 B2 2.900.80 0.30 0.012 0.035 0.029 0.0017 0.0011 0.0023 B3 2.90 0.80 0.30 0.0090.011 0.012 0.0025 0.0019 0.0031 B4 2.90 0.80 0.30 0.032 0.013 0.0210.0024 0.0034 0.0019 B5 2.90 0.80 0.30 0.012 0.032 0.029 0.0032 0.00140.0023 B6 2.90 0.80 0.30 0.034 0.012 0.043 0.0017 0.0032 0.0023 B7 2.900.80 0.30 0.009 0.005 0.004 0.0024 0.0032 0.0012 C1 2.70 0.45 0.80 0.0290.042 0.034 0.0023 0.0014 0.0017 C2 2.70 0.45 0.80 0.041 0.011 0.0150.0019 0.0023 0.0029 C3 2.70 0.45 0.80 0.024 0.029 0.023 0.0031 0.00190.0011 C4 2.70 0.45 0.80 0.021 0.041 0.041 0.0029 0.0019 0.0012 C5 2.700.45 0.80 0.042 0.029 0.013 0.0029 0.0021 0.0032 C6 2.70 0.45 0.80 0.0480.051 0.038 0.0014 0.0017 0.0021 C7 2.70 0.45 0.80 0.072 0.064 0.0360.0021 0.0021 0.0017

TABLE 4 Specimen Ti Nb B Mg Zr V Cu No. (%) (%) (%) (%) (%) (%) (%)Remarks B1 0.0023 0.0011 0.0005 0.0023 0.0032 0.0019 0.0171 Ex. B20.0032 0.0012 0.0007 0.0018 0.0017 0.0023 0.0087 Ex. B3 0.0017 0.00230.0002 0.0038 0.0019 0.0022 0.0066 Ex. B4 0.0012 0.0019 0.0018 0.00290.0041 0.0038 0.0059 Comp. Ex. B5 0.0017 0.0024 0.0004 0.0076 0.00140.0082 0.0174 Comp. Ex. B6 0.0021 0.0012 0.0007 0.0019 0.0078 0.00310.0423 Comp. Ex. B7 0.0029 0.0014 0.0003 0.0031 0.0021 0.0014 0.0121Comp. Ex. C1 0.0011 0.0024 0.0003 0.0016 0.0023 0.0021 0.0143 Ex. C20.0034 0.0011 0.0006 0.0035 0.0031 0.0029 0.0187 Ex. C3 0.0032 0.00120.0004 0.0019 0.0018 0.0034 0.0047 Ex. C4 0.0029 0.0019 0.0021 0.00370.0016 0.0026 0.0102 Comp. Ex. C5 0.0021 0.0023 0.0005 0.0021 0.00280.0017 0.0381 Comp. Ex. C6 0.0032 0.0021 0.0003 0.0018 0.0069 0.00720.0069 Comp. Ex. C7 0.0023 0.0029 0.0004 0.0081 0.0022 0.0030 0.0049Comp. Ex.

TABLE 5 Specimen Formula 1 Formula 2 Formula 3 B50 W15/50 W10/400Bending No. Value Value Value (T) (W/kg) (W/kg) test Elongation RemarksB1 2.64 56.76 0.104 1.70 1.98 15.3 Good 29.7 Ex. B2 2.64 56.76 0.0761.70 2.02 15.4 Good 30.2 Ex. B3 2.64 56.76 0.032 1.70 1.99 15.2 Good29.9 Ex. B4 2.64 56.76 0.066 1.66 2.14 16.9 Good 28.9 Comp. Ex. B5 2.6456.76 0.073 1.67 2.20 17.1 Good 30.7 Comp. Ex. B6 2.64 56.76 0.089 1.672.15 17.0 Good 30.2 Comp. Ex. B7 2.64 56.76 0.018 1.66 2.14 17.4 Good31.1 Comp. Ex. C1 2.16 53.37 0.105 1.71 2.03 15.9 Good 31.2 Ex. C2 2.1653.37 0.067 1.71 2.01 15.6 Good 30.1 Ex. C3 2.16 53.37 0.076 1.71 2.0115.7 Good 30.2 Ex. C4 2.16 53.37 0.103 1.67 2.19 17.9 Good 30.9 Comp.Ex. C5 2.16 53.37 0.084 1.68 2.18 17.7 Good 29.8 Comp. Ex. C6 2.16 53.370.137 1.68 2.24 18.1 Good 31.3 Comp. Ex. C7 2.16 53.37 0.172 1.67 2.1918.0 Poor 17.2 Comp. Ex.

As shown in Table 5, Examples B1, B2, B3, C1, C2, and C3, whichcorrespond to the range of the present disclosure, exhibited bothexcellent magnetic properties and good bend test results. On the otherhand, Examples B4, B5, B6, C4, C5, and C6 having a content of one ormore of B, Mg, Zr, V, and Cu above the range of the present disclosureexhibited inferior magnetic properties. Example B7 having the sum of P,Sn, and Sb contents below the range of the present disclosure exhibitedinferior magnetic properties, and Example C7 having the Mg content andalso the sum of Sn, and Sb contents exceeding the range of the presentdisclosure also exhibited inferior magnetic properties as well as poorbend test results and elongation.

It will be understood that the present disclosure is not limited to theabove embodiments but may be embodied in many different forms from eachother and those of ordinary skill in the art to which the presentdisclosure pertains can implement the invention in other specific formswithout changing the technical idea or essential features of the presentdisclosure. Accordingly, it will be understood that the exemplaryembodiments described above are only illustrative, and should not beconstrued as limiting.

1. A non-directional electrical steel sheet, comprising, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %) Ti, 0.005 wt % or less of (not including 0 wt %) Nb, 0.001 to 0.1 wt % of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, with the remainder being Fe and unavoidable impurities, and satisfying Formulas 1 to 3 below. 1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1] 50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2] 0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3] (In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent the content (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).
 2. The non-directional electrical steel sheet of claim 1, further comprising 0.001 wt % or less of (not including 0 wt %) B, 0.005 wt % or less of (not including 0 wt %) Mg, Zr and V and 0.025 wt % or less of (not including 0 wt %) Cu.
 3. The non-directional electrical steel sheet of claim 1, wherein a density of 7.57 to 7.67 g/cm³ is calculated by Formula 4 below. 7.865+(−0.0611*[Si]−0.102*[Al]+0.00589*[Mn])  [Formula 4] (In Formula 4, [Si], [Al] and [Mn] represent the contents (in wt %) of Si, Al and Mn, respectively.)
 4. The non-directional electrical steel sheet of claim 1, wherein a tensile test elongation is 24% or higher.
 5. The non-directional electrical steel sheet of claim 1, wherein a thickness is 0.10 to 0.35 mm.
 6. A method for manufacturing a non-directional electrical steel sheet, comprising steps of heating a slab comprising, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %) Ti, 0.005 wt % or less of (not including 0 Nb, 0.001 to 0.1 wt % of P, 0.001 to 0.1 wt of Sn, and 0.001 to 0.1 wt % of Sb, with the remainder being Fe and unavoidable impurities, and satisfying Formulas 1 to 3 below and then hot rolling the slab to manufacture a hot rolled sheet; cold rolling the hot rolled sheet to manufacture a cold rolled sheet; and recrystallization annealing the cold rolled sheet. 1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1] 50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2 ] 0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3 ] (In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent the content (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).
 7. The method of claim 6, wherein the step of manufacturing the hot rolled sheet comprises heating the slab at 1100 to 1200° C.
 8. The method of claim 6, wherein the step of manufacturing the hot rolled sheet comprises hot rolling at a finish temperature of 800 to 1000° C.
 9. The method of claim 6, after the step of manufacturing the hot rolled sheet, further comprising a step of annealing the hot rolled sheet at a temperature of 850 to 1150° C.
 10. The method of claim 6, wherein the slab further includes 0.001 wt % or less of (not including 0 wt %) B, 0.005 wt % or less of (not including 0 wt %) Mg, Zr and V and 0.025 wt % or less of (not including 0 wt %) Cu.
 11. The method of claim 6, wherein the manufactured steel sheet has a density of 7.57 to 7.67 g/cm³ as calculated by Formula 4 below. 7.865+(−0.0611*[Si]−0.102*[Al]+0.00589*[Mn])  [Formula 4] (In Formula 4, [Si], [Al] and [Mn] represent the contents (in wt %) of Si, Al and Mn, respectively.)
 12. The method of claim 6, wherein the manufactured steel sheet has a tensile test elongation of 24% or higher.
 13. The method of claim 6, wherein the step of manufacturing the cold rolled sheet comprises cold rolling at a thickness of 0.10 to 0.35 mm. 